Re: [PATCH -next V7 6/7] samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI]

From: Evgenii Shatokhin
Date: Mon Jan 16 2023 - 09:48:06 EST

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Hi,

On 12.01.2023 12:06, guoren@xxxxxxxxxx wrote:

From: Song Shuai <suagrfillet@xxxxxxxxx>

select HAVE_SAMPLE_FTRACE_DIRECT and HAVE_SAMPLE_FTRACE_DIRECT_MULTI
for ARCH_RV64I in arch/riscv/Kconfig. And add riscv asm code for
the ftrace-direct*.c files in samples/ftrace/.

Signed-off-by: Song Shuai <suagrfillet@xxxxxxxxx>
Tested-by: Guo Ren <guoren@xxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
---
arch/riscv/Kconfig | 2 ++
samples/ftrace/ftrace-direct-modify.c | 33 ++++++++++++++++++
samples/ftrace/ftrace-direct-multi-modify.c | 37 +++++++++++++++++++++
samples/ftrace/ftrace-direct-multi.c | 22 ++++++++++++
samples/ftrace/ftrace-direct-too.c | 26 +++++++++++++++
samples/ftrace/ftrace-direct.c | 22 ++++++++++++
6 files changed, 142 insertions(+)

The samples were built OK now, but ftrace-direct-multi and ftrace-direct-multi-modify report incorrect values of ip/pc it seems.

I ran 'insmod ftrace-direct-multi.ko', waited a little and then checked the messages in the trace:

# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
migration/1-19 [001] ..... 3858.532131: my_direct_func1: my direct func1 ip 0
migration/0-15 [000] d.s2. 3858.532136: my_direct_func1: my direct func1 ip ff60000001ba9600
migration/0-15 [000] d..2. 3858.532204: my_direct_func1: my direct func1 ip ff60000003334d00
migration/0-15 [000] ..... 3858.532232: my_direct_func1: my direct func1 ip 0
rcu_sched-14 [001] ..... 3858.532257: my_direct_func1: my direct func1 ip 0
insmod-415 [000] ..... 3858.532270: my_direct_func1: my direct func1 ip 7fffffffffffffff
<idle>-0 [001] ..s1. 3858.539051: my_direct_func1: my direct func1 ip ff60000001ba9600
<idle>-0 [001] dns2. 3858.539124: my_direct_func1: my direct func1 ip ff60000001ba9600
rcu_sched-14 [001] ..... 3858.539208: my_direct_func1: my direct func1 ip 0
[...]

If I understand it right, my_direct_func1() should print the address of some location in the code, probably - at the beginning of the traced functions.

The printed values (0x0, 0x7fffffffffffffff, ...) are not valid code addresses.

The same issue is with ftrace-direct-multi-modify.ko.

Is anything missing here?

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 307a9f413edd..e944af44f681 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -112,6 +112,8 @@ config RISCV
select HAVE_POSIX_CPU_TIMERS_TASK_WORK
select HAVE_REGS_AND_STACK_ACCESS_API
select HAVE_FUNCTION_ARG_ACCESS_API
+ select HAVE_SAMPLE_FTRACE_DIRECT
+ select HAVE_SAMPLE_FTRACE_DIRECT_MULTI
select HAVE_STACKPROTECTOR
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_RSEQ
diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index de5a0f67f320..be7bf472c3c7 100644
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -23,6 +23,39 @@ extern void my_tramp2(void *);

static unsigned long my_ip = (unsigned long)schedule;

+#ifdef CONFIG_RISCV
+
+asm (" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+" addi sp,sp,-16\n"
+" sd t0,0(sp)\n"
+" sd ra,8(sp)\n"
+" call my_direct_func1\n"
+" ld t0,0(sp)\n"
+" ld ra,8(sp)\n"
+" addi sp,sp,16\n"
+" jr t0\n"
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:\n"
+" addi sp,sp,-16\n"
+" sd t0,0(sp)\n"
+" sd ra,8(sp)\n"
+" call my_direct_func2\n"
+" ld t0,0(sp)\n"
+" ld ra,8(sp)\n"
+" addi sp,sp,16\n"
+" jr t0\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
#ifdef CONFIG_X86_64

#include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct-multi-modify.c b/samples/ftrace/ftrace-direct-multi-modify.c
index d52370cad0b6..10884bf418f7 100644
--- a/samples/ftrace/ftrace-direct-multi-modify.c
+++ b/samples/ftrace/ftrace-direct-multi-modify.c
@@ -21,6 +21,43 @@ void my_direct_func2(unsigned long ip)
extern void my_tramp1(void *);
extern void my_tramp2(void *);

+#ifdef CONFIG_RISCV
+
+asm (" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp1, @function\n"
+" .globl my_tramp1\n"
+" my_tramp1:\n"
+" addi sp,sp,-24\n"
+" sd a0,0(sp)\n"
+" sd t0,8(sp)\n"
+" sd ra,16(sp)\n"
+" call my_direct_func1\n"
+" ld a0,0(sp)\n"
+" ld t0,8(sp)\n"
+" ld ra,16(sp)\n"
+" addi sp,sp,24\n"
+" jr t0\n"
+" .size my_tramp1, .-my_tramp1\n"
+
+" .type my_tramp2, @function\n"
+" .globl my_tramp2\n"
+" my_tramp2:\n"
+" addi sp,sp,-24\n"
+" sd a0,0(sp)\n"
+" sd t0,8(sp)\n"
+" sd ra,16(sp)\n"
+" call my_direct_func2\n"
+" ld a0,0(sp)\n"
+" ld t0,8(sp)\n"
+" ld ra,16(sp)\n"
+" addi sp,sp,24\n"
+" jr t0\n"
+" .size my_tramp2, .-my_tramp2\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
#ifdef CONFIG_X86_64

#include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct-multi.c b/samples/ftrace/ftrace-direct-multi.c
index ec1088922517..a35bf43bf6d7 100644
--- a/samples/ftrace/ftrace-direct-multi.c
+++ b/samples/ftrace/ftrace-direct-multi.c
@@ -16,6 +16,28 @@ void my_direct_func(unsigned long ip)

extern void my_tramp(void *);

+#ifdef CONFIG_RISCV
+
+asm (" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi sp,sp,-24\n"
+" sd a0,0(sp)\n"
+" sd t0,8(sp)\n"
+" sd ra,16(sp)\n"
+" call my_direct_func\n"
+" ld a0,0(sp)\n"
+" ld t0,8(sp)\n"
+" ld ra,16(sp)\n"
+" addi sp,sp,24\n"
+" jr t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
#ifdef CONFIG_X86_64

#include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index e13fb59a2b47..3b62e33c2e6d 100644
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -18,6 +18,32 @@ void my_direct_func(struct vm_area_struct *vma,

extern void my_tramp(void *);

+#ifdef CONFIG_RISCV
+
+asm (" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi sp,sp,-40\n"
+" sd a0,0(sp)\n"
+" sd a1,8(sp)\n"
+" sd a2,16(sp)\n"
+" sd t0,24(sp)\n"
+" sd ra,32(sp)\n"
+" call my_direct_func\n"
+" ld a0,0(sp)\n"
+" ld a1,8(sp)\n"
+" ld a2,16(sp)\n"
+" ld t0,24(sp)\n"
+" ld ra,32(sp)\n"
+" addi sp,sp,40\n"
+" jr t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
#ifdef CONFIG_X86_64

#include <asm/ibt.h>
diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index 1f769d0db20f..2cfe5a7d2d70 100644
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -15,6 +15,28 @@ void my_direct_func(struct task_struct *p)

extern void my_tramp(void *);

+#ifdef CONFIG_RISCV
+
+asm (" .pushsection .text, \"ax\", @progbits\n"
+" .type my_tramp, @function\n"
+" .globl my_tramp\n"
+" my_tramp:\n"
+" addi sp,sp,-24\n"
+" sd a0,0(sp)\n"
+" sd t0,8(sp)\n"
+" sd ra,16(sp)\n"
+" call my_direct_func\n"
+" ld a0,0(sp)\n"
+" ld t0,8(sp)\n"
+" ld ra,16(sp)\n"
+" addi sp,sp,24\n"
+" jr t0\n"
+" .size my_tramp, .-my_tramp\n"
+" .popsection\n"
+);
+
+#endif /* CONFIG_RISCV */
+
#ifdef CONFIG_X86_64

#include <asm/ibt.h>
--
2.36.1

Regards,
Evgenii

Next message: Konrad Dybcio: "Re: [PATCH v9 6/6] arm64: dts: qcom: msm8998: Configure CPRh"
Previous message: Linus Walleij: "Re: [PATCH v1 1/1] gpio: Remove unused and obsoleted irq_to_gpio()"
Next in thread: Song Shuai: "Re: [PATCH -next V7 6/7] samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI]"
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